Two-stroke-cycle internal-combustion engine



1925- H. P. scHurTLER TWO-STROKE CYCL INTERNAL COIBUS'EION ENGINE Oct. 13

Filed Jan. 25, 1924 2 Sheets-Sheet l Oct. 13I ,1925- H. P. SCHUTTLER TWO-STROKE CYCLE INTERNAL COMBUSTION ENGINE Filed Jan. 25. 192.4 2 Sheets-Sheet 2 Rvws hapert/F H'P Schr/bale,

Patented Oct. 13, 1925.

UNITED STATES HIERONYMUS PAUL SGHUTTLER, OF CHARLOTTENBURG, GERMANY.

TWO-STROKE-CYCLE INTERNAL-CMBUSTION ENGINE.

Application filed January 25, 1924. Serial No. 688,576.

To all whom t may cof/warm Be it known that I, I-IIEnoNYMUs PAUL SGHUTTLEP., a German citizen, of Charlottenburg, Germany, have invented certain new and useful Improvements Relating to 'I wo- Stroke-Gycle Internal- Combustion Englnes, of which the followingis aspeciiication.

This invention relates to two-stroke cycle' internal combustion engines and has for its object to provide for the more complete charging of the engine cylinder or cylinders with combustible mixture at each stroke, and for the more effective expulsion of the burnt gases or products of combustion without admiXture of the same with the combustible charge'.

The invention comprises the improved construction of engine and combinations and arrangements of parts hereinafter described and claimed.

Referring to the accompanying sheets of explanatory drawings Figure 1 is a sectional elevation of a two stroke cycle engine constructed inv one convenient form in accordance with my inven-V tion. 1

Figure 2 is a sectional plan View on the line AB of Figure 1.

Figure 3 is a sectional elevation rf the upper part of an engine showing a modified construction of same. l

Figure 4 is a sectional elevation on the line DEF of Figure 5, and Figure 5 a sectional plan view on the line GH of Figure 4 showing a further modified construction of engine. y

The same reference letters in the ,liil'erent l ,views indicate the same or similar parts.

Referring in the rstplace toFigures 1 to 2, the engine proper comprises a: piston a having a sleeve or skirt 'like extension b thereon which slides within an annul-ar recess provided between the cylinder wall c and the cylinder head d. The skirt b -has ports' e therein for placing theinterior of the back e ofthe piston in communication with the eX- haust ports fand ports g for placing the said interior of the piston in communication with the transfer passages by which the combustible charge from the engine crank case is passed into the said piston. The carburettor i supplies the crank case with a combustible charge for compression purposes inthe known manner each time the piston a rises or moves outwards.

`The cylinder head d is ribbedv as shown to and on the in or do'wnstroke of the piston tends to create a vacuumv in said annular recess. The ports j in the cylinder walls are of such small dimensions ihat such vacuum is only partially destroyed by a withdrawal from the transfer passage L, so that when the piston reaches or approaches the end of its inward or power stroke, there is still a considerable degree of Vacuum in said annular recess. This is broken by air drawn therein'through the ports Zi in the c linder head. The effect of the rush of air. t rough the ports 7c is to cause an inflow of yfresh airto the interior of the cylinder head which cools the said head. The circulation of air in the said recess and through the ports j also tends to keep the lskirt or sleeve b cool.

Ifdesired, I may as shown in Figure 3, fit a non-return valve u upon each passage j so that during the power stroke of the piston a, a vacuum is formed in the annular recess before referred to until the ports vl: are uncovered, when air isadluittcd to said recess. During the return stroke ofthe piston, free delivery takes place of pure air into the passages h. The non-return valves u each consist of a disc with an adjustable stop piece @for limiting the opening Inovement of the disc.

Due to the formation of the piston a with a sleeve portion b, the area of the piston at t-he crank case -side which acts to pump and compress the combustible charge is greater than the effective area'of the opposite side of the piston so that a full charge or a super-charge is received by the exigne at each `stroke under, full power conditions, that is when lhe 'crank chamber is receiving a full charge.

It willbe seen that by arranging two transfer ports h at opposite sides of the cylinder near the end face of the cylinder head d in which the sparking plug is fitted, and the exhaust ports e at opposite sides of the piston near its lower end, I obtain a uniform iow eii'ect through the cylinder, the charging taking place at one end and eX- haustion at the other end. By this means, expulsion of the exhaust gases without adports way of a port passage and a channel s formed around the engine cylinder and leadinor to the said transfer With this construction,'when the piston a is ap roaching the end of its outward stroke and the combustible charge is being drawn into the crank chamber, the

into t e channels and transfer passage h.

' When, therefore,'the transfer passage is plit in t esleeve or skirt b, practically pure alr passes into communication with the port first into .the piston followed by the combustible charge. The said pure air assists in the expulsion of the. products of combustion from the istonl and prevents contamination or admlxture of`the combustible.

charge with the same.

stead of compressing a combustible charge in the engine crank case,iI may compress` pure air only therein and mix the fuel there- Awith as it passes into the engine vpiston or in the transfer passages. Ordinary and well known methods of adding fuel to the air consist of y(l) balanced carburettors each spraying into a Venturi tube through which the air venters the engine piston and (2) spray nozzles, each with aupump ,appropriately timed to inject fuel into thev engineat the correct instant. n l

Iclaimz-l f 1. In a two-stroke cycle internal combustion engine, a cylinder, a crank chamber, a head extending into the cylinder and having a portion spaced from t e latter to provide .an annular recess between the head and cylinder, a spark plu dis p osed withinsaid head, a piston in sai cy. inder having asleeve thereon working in said: annular recess, a transfery passageway for leading', fuel come pressed in the crank chamber to the interior ofthe cylinder, andmeans whereby the pis#l ton sleeve controls the admission of external I I air tothe transfer vpassageway and/permits and r come into line and air is drawn Luana? said air to enter the engine cylinder before the ordinary combustible mixture charge enters the cylinder from said passageway.

2. In a two stroke cycle internal combustion engine as claimed in claim 1,the sleeve snugly fitting in the annular recess so as to produce a partial vacuum in the recess during the outward stroke of the piston, means for admitting air into the annular recess Iat about the end of the outward stroke of.the piston, and a conduit for transferring air admitted to said annular recess,` to said transfer passageway.

3. In a two stroke cycle internal combustion engine as claimed in claim 1, the sleeve snugly fitting in theannular recess so as to roduce a partial vacuum-.in the recess during the outward stroke of the piston, means ,l the transfer passageway into said recess. It vwill of course be understood thatin- 4. In a two-strokecycle internal combustion engine, a cylinder, ahead extending into the cylinder andd having a portion spacing from the latter to provide an annular recess between the head and cylinder, a piston in said cylinder having a sleeve thereon working in the annular recess. two inlet ports in said sleeve at diametrially opposite points, two exhaust ports in said sleeve also at diametrically opposite points and spaced circumferentially between the said inlet ports, two inlet ports, a crank chamber, 'transfer passageways in the cylinder leading from the crank chamber and adapted to introduce a compressed combustible mixture from the crank chamber through said inlet ports into the cylinder, a spark plug port arranged centralhr within the eylinder head,

.and means whereby" the piston sleeve causes the combustible `mixture from the transfer passagewaysto the interior of the cylinder. ,'ffn testimony whereof ,Ilghave signed my )name ,to this specification.'y

. y f menomus PAUL scauri'uaz.Y 

